Optimization Of Enzymatic Activity Of Protease A From Beer By UV Spectrophotometry

Presently,ultraviolet spectrophotometry,Lowry,Bradford,substrate fluoresc ence and resonance scattering method have been used for the detection of prot ease A activity in beer industry.The methods above are suitable for the detecti on of samples with higher protease A concentration.A large number of studies have shown that the results from using the UV method for the detection of pr otease A activity in beer is still credible in the range of 200 ~ 2000?g/mL(th e concentration of protease A in beer),but there is still room for improvement.This study mainly focused on the optimization of ultraviolet spectrophotometry in order to achieve A rapid and accurate determination of protease A activity in beer according to the actual situation of Sichuan Yanjing beer co.LTD.In this study,the protease A activity in the 9.5°P beer(including draft be er and pasteurimd beer)and 8°P beer(including draft beer and pasteurimd bee r)was detect by using ultraviolet spectrophotometer.Results indicated that the absorbance value fluctuated greatly,sometimes appeared to negative values with the increase of dilution multiple.Therefore,the ultraviolet spectrophotometer method was optimized from several aspects,such as the change of blank contr ol group,the best wavelength,the reaction time and the reagent concentration.The improved method was as follows: the concentration of casein was changed to 5000 mg/L,the concentration of trichloroacetic acid was 1.25 mol/L,the r eaction time was still 10 min,and the reaction wavelength was still 275 nm.Fi nally,in order to verify whether the improved method is superior to the origin al method,the activity of protease A was detected by diluting the beer by 2,3 and 4 times,respectively.The results show that The absorbance values deter mined by the improved method are all positive numbers,and the calculated act ivity of protease A is closer to the activity of protease A in the actual product ion beer.At the same time,based on the results of our research and related re ferences,the corresponding suggestions on improving the stability of beer foam in practical production and beer storage are put forward,and the future devel opment is also discussed.